SLONM with MGUS: long term follow-up after melphalan and SCT13 October 2018

Appendix e-1: Methods

Study design. We performed a retrospective case series (n=8) on the long-term (nine months – eight years) treatment effect of HDM followed by autologous SCT.

Setting. Diagnosis and treatment of all patients was performed in tertiary referral centers for neuromuscular disorders and hematological diseases respectively.

Participants, study size, bias and data sources. All eight patients were diagnosed by the neurologists in four tertiary referral centers for neuromuscular disorders(Radboud university medical centre, Nijmegen, The Netherlands; Hôpital Pitié Salpêtrière, Myology Institute, Paris, France; and Neuromuscular Reference Centre, Cliniques universitaires Saint-Luc, University of Louvain, Brussels, Belgium; and Lausanne University Hospital CHUV, Lausanne, Switzerland).The series includes the two patients reported in 20081, 2 and the patient reported in 20103, The other five patients had not been reported in literature.We included all eight known cases with this rare disorder in these centers to prevent a selection bias. These tertiary referral centers are connected to several regional neuromuscular services, thus reducing the risk of observational bias.

Standard Protocol Approvals, Registrations, and Patient Consents.All data were collected within usual care protocols and stored anonymously. Therefore the ethical committees approved our study without a formal application process and without the request for informed consent. However, we informed all our patients about this study, and they gave their written consent anyhow.

Research question

The primary research question concernsthe qualitative evaluation of the long-term treatment response of HDM followed by autologous SCT in SLONM-MGUS patients on survival, muscle strength and functional capacities. In this design, this will result in level IV evidence.

Variables. Muscle strength and functional outcome. Long-term follow-up after treatment was possible in all patients, ranging from nine months up to eight years. Information was obtained from patients’ records or from the patients or their families regarding clinical status, therapy received, response to therapy, including functional recovery.Muscle strength was assessed with manual muscle testing (MRC scores 0 to 5), and muscle weakness was subsequently classified as 0 (MRC 5 in muscles of UL / LL); + (MRC4); ++ (MRC3); or +++ (MRC 0-1-2).Functional measurements included the Brooke Scale (measures upper extremity function; 1= starting with the arms at the sides the patient can abduct the arms in a full circle until they touch above the head; 2 = can raise arms above head only by flexing the elbow or using accessory muscles; 3 = cannot raise arms above head, but can raise an 8-oz glass of water to mouth; 4 = can raise hands to mouth but cannot raise an 8-oz glass of water to mouth; 5 = cannot raise hands to mouth but can use hands to hold pen or pick up pennies from the table; 6 = cannot raise hands to mouth and has no useful function of hands), 10 m walk test, and the Walton clinical severity score (W CSS: 0 = preclinical, all activities normal; grade 1 = normal walking, unable to run freely; grade 2 = detectable defect in posture or gait, climbs stairs without use of banister; grade 3 = climbing stairs only with banister; grade 4 = walks without assistance, unable to climb stairs; grade 5 = walks without assistance, unable to rise from a chair; grade 6 = walks only with calipers or other aids; grade 7 = unable to walk, sits erect in a chair, able to roll a wheelchair and eat and drink normally; grade 8 = sits unsupported in chair, unable to roll wheelchair or unable to drink from a glass unassisted; grade 9 = unable to sit erect without support of unable to eat or drink without assistance; 10 = confined to bed; requires help for all activities).4, 5

Muscle biopsies.Muscle biopsies were performed by needle or open biopsies, and the side of the biopsy is presented in table 1 (: VL= vastus lateralis muscle; D = deltoid muscle; BB = biceps brachii muscle). Biopsies were processed for histochemical analysis and electronmicroscopy as described previously.6 Gomori-Trichrome staining and alfa-actinine immunohistochemistry was used to visualize rods. Electronmicroscopy was performed in six patients.

DNA diagnostics. The results of previously performed DNA tests were noted from the medical records.

Hematological analysis. Blood samples from all patients were analyzed for electrophoresis and if an M-protein was detected, immunofixation was performed. A bone marrow biopsy was performed to measure the percentage of plasma cells. Patients were analyzed for possible symptomatic multiple myeloma by further blood testing for hemoglobin, creatinin and calcium levels and a skeletal survey was performed to detect possible lytic lesions. Of note, hematological analyses were performed in the local laboratories. Therefore, quantification of M-protein has been performed according to local standards, and might not be completely comparable between the different centers. Longitudinal data within one patient will of course not be influenced by this.

Qualitative evaluation of treatmentresponse. To evaluate the effect of HDM and SCT on the disease course, we classified the overall clinical response as:(I) lasting moderate - good response (increase of muscle strength of at least two muscle groups on MMTand any functional improvement during follow-up); (II) temporarily moderate – good(initial increase of muscle strength of at least two muscle groups on MMT andany functional improvement with secondary decrease of muscle strength of at least two muscle groups on MMT during follow-up); (III) poor (no increase of muscle strength of at least two muscle groups on MMT or not any functional improvement but slowing of the pre-treatment clinical deterioration); and (IV) no response (no alteration of the pre-treatment disease course).

We compared the following characteristics of the patients to evaluate the hematological response: level and type of M-protein and result of bone marrow biopsy (kappa vs. lambda; percentage plasma cells ≤ 10% MGUS vs. > 10% multiple myeloma; other treatments before the SCT; other treatments following the SCT (chemotherapy, immunosuppression, rehabilitation); hematological response to the HDM with SCT and to other chemotherapy. This was classified according to international criteria (International Myeloma Working Group uniform response criteria): complete response (CR: no M-protein in serum and urine and ≤ 5% plasma cells in bone marrow); very good partial response (VGPR: M-protein only detectable on electrophoresis or ≥ 90% reduction of M-protein in serum), partial response (PR: ≥ 50% reduction of serum M-protein and ≥ 90% reduction of 24-hr urine M-protein) and no response (SD: stable disease) and progressive disease (PD: Increase of > 25% from lowest response value in any M-protein level).7

Statistical methods. We used no statistical methods in this retrospective observational study.

References

1.Voermans NC, Minnema M, Lammens M, et al. Sporadic late-onset nemaline myopathy effectively treated by melphalan and stem cell transplant. Neurology 2008;71:532-534.

2.Benveniste O, Laforet P, Dubourg O, et al. Stem cell transplantation in a patient with late-onset nemaline myopathy and gammopathy. Neurology 2008;71:531-532.

3.Novy J, Rosselet A, Spertini O, Lobrinus JA, Pabst T, Kuntzer T. Chemotherapy is successful in sporadic late onset nemaline myopathy (SLONM) with monoclonal gammopathy. Muscle & Nerve 2010;41:286-287.

4.Brooke MH, Griggs RC, Mendell JR, Fenichel GM, Shumate JB. The natural history of Duchenne muscular dystrophy: a caveat for therapeutic trials. Transactions of the American Neurological Association 1981;106:195-199.

5.Gardner-Medwin D. The clinical examination of the voluntary muscles. In: Walton JN, ed. Disorders of voluntary muscles. Edinburgh and London: Churchill-Livingstone 1974.

6.Voermans NC, van Alfen N, Pillen S, et al. Neuromuscular involvement in various types of Ehlers-Danlos syndrome. Annals of Neurology 2009;65:687-697.

7.Durie BG, Harousseau JL, Miguel JS, et al. International uniform response criteria for multiple myeloma. Leukemia 2006;20:1467-1473.

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